The invention relates to a locking device permitting the movement, at any one time, of only one of two push buttons each associated with an electrical switch and having substantially parallel directions of actuation. The device is of the kind in which, between two operating members each associated with one of the buttons, there is disposed the axis of a pivotable bolt having two ends one of which is displaced by the movement of a first member in such a manner that the other becomes placed in the path of the second element.
Such devices are advantageously used in pendant boxes utilised for the control of lifting apparatus.